Locking device

ABSTRACT

A locking device utilizing a part-circular disc which, when rotated, serves to lock concentric cylindrical parts against axial or rotary movement or both, the disc then being retained in its rotated position to retain this locking arrangement.

United States Patent Steinbarger 51 Feb. 22, 1972 [54] LOCKING DEVICE2,722,373 11/1955 Ledwith et a1. 415/218 2,766,693 10/1956 Zimmerman415/218 [72] Jay Steinbarge 3,069,135 12/1962 Welsh ....415/218 [73]Assignee: General Motors Corporation, Detroit, 3,295,751 1/ 1967 Sceggel..415/2l9 Mich. FOREIGN PATENTS OR APPLICATIONS [22] F11ed: Sept. 21,1970 873,759 7/1961 Great Britain ..415/217 [21] Appl. No.: 74,008

Primary Examiner-Henry F. Raduazo 52 us. 01... ..'......'.41s/21s,415/199, 415/219 Arrorneylean L. Carpenter and Arthur Krein [51] Int. Cl..F04d 29/40, F04d 29/00, FOld 9/00 [58] Field otSearch ..415/193,194,199,216,217, [57] ABSTRACT 415/218" 219 A locking deviceutilizing a part-circular disc which, when rotated, serves to lockconcentric cylindrical pans against [56] Reterences cued axial or rotarymovement or both, the disc then being retained UNITED STATES PATENTS inits rotated position to retain this locking arrangement.

2,543,355 2/1951 Davis et a1. ..4l5/218 8 Claims, 6 Drawing FiguresPAIENTEDFEB22 I912 3.644.057

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NVENTOR.

A T TOPNEY LOCKING DEVICE This invention relates to a locking deviceand, in particular to a locking device for use in an axial flow turbineor similar device to lock concentric cylindrical parts against axial orrotary movement or both.

A known type of multistage axial flow gas turbine includes a pluralityof external casing rings that are bolted together to form a turbinecasing assembly in which are mounted a plurality of stator vaneassemblies as by being peripherally flanged thereto for support. Such agas turbine structure is disclosed in the US. Pat. No. 2,766,963, issuedon Oct. 16, 1956, to Donald G. Zimmerman. In various such turbineassemblies, it has been difficult to mount the stator assemblies withinthe turbine casing to maintain a predetermined axial alignment of thestator assemblies within the engine housing or to fix the statorassemblies rotatively with respect to the turbine housing except byproviding radially extending flanges on the stator assemblies which canbe secured to suitable flanges formed on the turbine casing assembly,for example, as disclosed in the above identified U.S. Pat. No.2,766,963.

Accordingly, the primary object of this invention is to provide a lockwhereby to secure concentric cylindrical parts together against axial orrotary movement or both with respect to each other.

Another object of this invention is to provide a locking device ofsimple construction whereby to permit assembly and then locking togetherof concentric cylindrical parts.

These and other objects of the invention are obtained by means of alocking device in which a part-circular disc, having a semicircularaperture in the chord thereof is positioned in a semicircular spot-faceopening in at least one flanged surface of a pair of radially extendingflanges on outer tubular casings, the disc then being rotated to bringit into engagement with a groove, semicircular slot or semicircularspot-face opening in a concentric inner tubular mating piece. Theflanges are bolted together with the bolt engaged in the semicircularaperture in the chord portion of the disc to lock it against rotationwhereby the mating piece is thus secured by the part-circular discagainst axial movement or rotary movement or both.

For a better understanding of the invention, as well as other objectsand further features thereof, reference is had to the following detaileddescription of the invention to be read in connection with theaccompanying drawings, wherein:

FIG. 1 is a sectional view of a portion of a turbine casing and statorassembly coupled together utilizing a locking device in accordance withthe invention;

FIG. 2 is an enlarged view of a portion of FIG. 1 showing the lockingdevice of the invention in locked position;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2 with a lockingdevice being shown in locked position and another locking device beingshown in an unlocked position;

FIG. 4 is an exploded perspective view of another embodiment of thelocking arrangement of the invention;

FIG. 5 is a view similar to FIG. 2, but utilizing still another lockingarrangement of the invention; and,

FIG. 6 is an exploded perspective view of the locking arrangement ofFIG. 5.

Referring now to the drawings in detail, the turbine assembly comprisestwo major components, a turbine rotor assembly and a turbine casingassembly. The turbine casing assembly includes an outer casing structurethat encircles the blade system of the turbine and an inner casingstructure supported thereby and defining therewith the inlet and exhaustportions of the turbine and providing bearing support for the turbinerotor assembly. The outer casing structure includes a rigid multi-partexternal casing structure and a segmented, relatively flexible,stator-vane internal casing structure secured thereto. The turbine rotorassembly includes a bladed drum built up from alternating bladed discsand nonbladed spacer discs. The forenoted turbine construction may beconventional and therefore only so much of the structure as is necessaryto enable one skilled in the art to understand the invention asillustrated.

A rear casing 10, an intermediate casing 12 and a forward casing 14which comprise the primary structure components of the turbine casingassembly are bolted together at 16 and 18, the rear casing 10 supportingan exhaust casing structure, not shown. The forward casing 14 forms partof an inlet casing structure which includes an inner casing 20 and aforward bearing support plate 22 supported therefrom by radialconstruction, not shown. The turbine rotor assembly 24 includes bladediscs 26 and spacer discs 28 suitably secured together for rotation inthe turbine casing in the usual manner. The outer casing structureincludes stator-vane assemblies supported from the casing 10, 12 and 14by peripheral tongue and groove structures and held in axial alignmentby a locking device in accordance with the invention, to be describedhereinafter.

The stator-vane assemblies form the fixed blading for the turbine and aninternal casing structure for the turbine casing assembly. Thestator-vane assemblies include the outer shroud rings 30, 32, 34 and 36and the inner shroud rings 38 secured thereto by the stator-vanes 40,the first stage inner shroud ring being additionally supported by theinner casing 20 and the remaining inner shroud rings serving as gasseals between the blading stages of the turbine rotor. Preferably, aheat shield 42 encircles the outer shroud 36.

The turbine unit is assembled with the outer shroud rings secured to theturbine casing in a manner to be described. As shown, the externalcasings 10 and 14 are formed with peripheral tongues 44, 46 and 48 thatextend axially to support the stator-vane assemblies. The outer shroud30 is formed at one end with a peripheral flange 50 received in theannular groove formed by tongue 44 of casing 10 and the inner surface ofcasing 12, and at its other end with a peripheral groove 52. Shroud 32is also provided at opposite ends with a peripheral flange 54 receivedin groove 52 of shroud ring 30 and a peripheral groove 56. Outer shroudring 34 is also provided at one end with a peripheral flange 58 receivedin the peripheral groove 56 of shroud ring 32 and at its other end withan axially extending shoulder portion 60 and peripheral groove 62, theshoulder portion 60 being received in the groove formed by tongue 46 ofcasing 14. Outer shroud ring 36 is provided with peripheral flanges 64and 66 received in the groove 62 of shroud ring 34 and in the grooveformed by tongue 48 of forward casing 14, respectively, the heat shield42 also being engaged in these same grooves. Because a considerabletempera ture differential exists between the shroud ring assemblies andthe external casing during engine operation, suitable clearances areprovided between the tongue and groove fittings, just described, topermit for limited axial and radial expansion of the various assemblieswith respect to each other.

At least one shroud ring, preferably an intermediate outer shroud ringsuch as ring 34, is fixed at one end axially with respect to theexternal casing and may, if desired, also be locked to prevent relativerotation with respect to the external casing by the use ofcircumferentially spaced apart locking devices 70, in accordance withthe invention, engaged in suitable key slots formed in the outer shroudring.

Referring now in part to FIGS. 1, 2 and 3, each locking device 70 is inthe form of a part-circular disc or key having a circular edge portion72 and a flat or chord portion 74 provided with semicircular notch 76 inthe center thereof.

Each of the locking devices 70 is mounted in a semicircular spot-face 78in the end wall of the flange 68 of intermediate casing 12 such that,when in an unlocked position, as shown by the right-hand locking devicein FIG. 3, the chord portion 72 of the locking device is positioned outof engagement with the outer periphery of the outer shroud ring 34. Toeffect locking of the outer shroud ring 34 to the outer casing, thelocking device 70 is rotated so that the circular edge portion 72 isrotated into a key slot 80 provided in the outer shroud ring 34. Asshown in the embodiment of FIG. 3, the key slot 80 in this particularembodiment is in the form of a continuous annular slot of a suitabledepth and width to receive the locking device 70. To facilitate rotationof the locking devices 70 from the unlocked to the locked position, asuitable screw driver slot 82 or other suitable aperture can be providedin each locking device70 to receive a tool such as a screw driver forconvenience in rotating the disc.

After rotation of all of the locking devices to the locked position, theposition of the left-hand lock disc of FIG. 3, the rear casing 14 canthen be secured to the intermediate casing 12 by means of bolts 18 witha bolt 18 being engaged in the semicircular notch 76 of the lockingdevice to lock the disc against rotation. With this arrangement, theouter shroud ring 34 is secured to the outer casing to prevent axialmovement in both directions relative thereto while still being free torotate relative to the external casing.

Referring now to the embodiment shown in FIG. 4, instead of the annularkey slot 80, previously described, individual key slots 800 are providedin the outer shroud ring 34. In this embodiment, each of the key slots80a are in the form of semicircular recesses of the desired diameter andwidth for the locking device 70 to be used therein. With thisarrangement, the outer shroud ring 34 is secured against axial movementin both directions and against rotation with respect to the outercasing.

In the embodiment illustrated in FIGS. 5 and 6, the key slot is in theform of individual spot-face slots 80b for each of the locking devices70 provided in the outer edge of the outer shroud ring 34, eachspot-face being of the appropriate diameter and width to accommodate alocking device 70 when in the locked position, as seen in FIG. 5. Thisconfiguration of the key slot to receive the locking device will preventaxial movement of the outer shroud ring 34 in one direction only butwill prevent rotation in both directions of the outer shroud ring withrespect to the outer casing.

Although the spot-faces 78 have been shown as being formed in only oneof the two mating flanges of the casings l2 and 14, it is to be realizedthat if so desired, both flanges can be spot-faced to the desired depthto accommodate the locking devices between the two flanges.

What is claimed is:

1. An elastic fluid turbine including a plurality of flanged casingrings secured together by bolts to provide an annular casing, astator-vane shroud ring assembly disposed in said casing, a peripherallyextending tongue and groove structure on said casing and said shroudring assembly for mounting said shroud ring assembly in said casing, aplurality of circumferentially spaced apart semicircular spot-faceopenings in the end surface of one of said flanged casing rings, keyslot means in the peripheral surface of said shroud ring assembly, and

particularly key discs positioned in said spot-face openings inengagement in said key slot means, said key discs including retainingmeans thereon engaged by said bolts to secure said particular key discsin engagement in said key slot means.

2. An elastic fluid turbine according to claim 1 wherein each of saidpart-circular key discs is provided with a circular edge portion and achord portion with a semicircular notch in the center thereof and eachof said key discs is adapted to be rotatively positioned in one of saidspot-face openings for movement from a position in which said circularedge portion is out of engagement with said shroud ring assembly to aposition in which said circular edge portion is in engagement with saidkey slot means in said shroud ring assembly.

3. An elastic fluid turbine according to claim 2 wherein said key slotmeans is an annular groove in said shroud ring assembly.

4. An elastic fluid turbine according to claim 2 wherein said key slotmeans is a plurality of circumferentially spaced apart semicircularrecesses in said shroud ring assembly of a diameter and width to receivesaid circular edge portions of said key discs.

5. An elastic fluid turbine according to claim 2 wherein said retainingmeans is provided by said semicircular notch in said chord portion beingengaged by one of said bolts in said flanged casing rings.

A locking device for securing concentric cylindrical outer and innerparts together, the outer part including a pair of flanged hollowmembers secured together by bolts, a plurality of circumferentiallyspaced apart semicircular spot-face openings in the end surface of oneof said flanged hollow members, key slot means in the peripheral surfaceof said inner part, a plurality of part-circular key discs each providedwith a circular edge portion and a chord portion with a semicircularnotch inthe center of said chord portion positioned in said spot-faceopenings for movement from a position in which said circular edgeportion is out of engagement with said inner part to a position in whichsaid circular edge portion is in engagement with said key slot means insaid inner part, one of said bolts engaging said semicircular notch insaid chord portion when said circular edge portion is in engagement withsaid key slot means to retain said part-circular key disc againstrotative movement in said spot-face opening.

7. A locking device according to claim 6 wherein said key slot means isan annular groove in said inner part.

8. A locking device according to claim 6 wherein said key slot means isa plurality of circumferentially spaced apart, semicircular recesses insaid inner part of a diameter and width to receive said circular edgeportions of said key discs.

1. An elastic fluid turbine including a plurality of flanged casingrings secured together by bolts to provide an annular casing, astator-vane shroud ring assembly disposed in said casing, a peripherallyextending tongue and groove structure on said casing and said shroudring assembly for mounting said shroud ring assembly in said casing, aplurality of circumferentially spaced apart semicircular spot-faceopeniNgs in the end surface of one of said flanged casing rings, keyslot means in the peripheral surface of said shroud ring assembly, andparticularly key discs positioned in said spot-face openings inengagement in said key slot means, said key discs including retainingmeans thereon engaged by said bolts to secure said particular key discsin engagement in said key slot means.
 2. An elastic fluid turbineaccording to claim 1 wherein each of said part-circular key discs isprovided with a circular edge portion and a chord portion with asemicircular notch in the center thereof and each of said key discs isadapted to be rotatively positioned in one of said spot-face openingsfor movement from a position in which said circular edge portion is outof engagement with said shroud ring assembly to a position in which saidcircular edge portion is in engagement with said key slot means in saidshroud ring assembly.
 3. An elastic fluid turbine according to claim 2wherein said key slot means is an annular groove in said shroud ringassembly.
 4. An elastic fluid turbine according to claim 2 wherein saidkey slot means is a plurality of circumferentially spaced apartsemicircular recesses in said shroud ring assembly of a diameter andwidth to receive said circular edge portions of said key discs.
 5. Anelastic fluid turbine according to claim 2 wherein said retaining meansis provided by said semicircular notch in said chord portion beingengaged by one of said bolts in said flanged casing rings.
 6. A lockingdevice for securing concentric cylindrical outer and inner partstogether, the outer part including a pair of flanged hollow memberssecured together by bolts, a plurality of circumferentially spaced apartsemicircular spot-face openings in the end surface of one of saidflanged hollow members, key slot means in the peripheral surface of saidinner part, a plurality of part-circular key discs each provided with acircular edge portion and a chord portion with a semicircular notch inthe center of said chord portion positioned in said spot-face openingsfor movement from a position in which said circular edge portion is outof engagement with said inner part to a position in which said circularedge portion is in engagement with said key slot means in said innerpart, one of said bolts engaging said semicircular notch in said chordportion when said circular edge portion is in engagement with said keyslot means to retain said part-circular key disc against rotativemovement in said spot-face opening.
 7. A locking device according toclaim 6 wherein said key slot means is an annular groove in said innerpart.
 8. A locking device according to claim 6 wherein said key slotmeans is a plurality of circumferentially spaced apart, semicircularrecesses in said inner part of a diameter and width to receive saidcircular edge portions of said key discs.